1. Field of the Invention
The present invention relates to a digital multimedia broadcasting (DMB) receiver and a channel estimation method of the DMB receiver and, more particularly, to a technique of estimating DMB channels to compensate for distortion in DMB signals.
2. Description of Related Art
With the development of the Internet and media, the type of information has evolved from text to multimedia data, such as images, audio, and video.
DMB is a digital transmission system for sending multimedia data to mobile devices such as mobile phones. Fading due to multipath propagation is a major factor in the deterioration of DMB quality. The fading due to multipath propagation results from the superposition of transmitted DMB signals which have experienced differences in attenuation, delay and phase shift while traveling from a source to a DMB receiver. Thus, in the DMB receiver, channel estimation is required to compensate for channel distortions in the phase and amplitude of DMB signals due to the fading phenomenon.
FIG. 1 is a frame structure of a pilot channel signal in DMB.
The pilot channel signal in DMB has a frame structure consisting of a plurality of pilot symbols PS, a unique word D1, a frame counter D2, CDM channel control data D3˜D22 and D27˜D46, forward error correction (FEC) symbols D23˜D26 and D47˜D50, and extension information D51. The pilot symbol is a synchronous signal, the unique word is a frame synchronous signal, and the frame counter is a superframe synchronous signal.
FIG. 2 is a channel estimation diagram of a conventional DMB receiver.
Conventionally, a channel estimation process is performed using a pilot symbol PS of a pilot channel signal. That is, since the pilot symbol PS of the pilot channel signal is set to a 32-bit synchronous signal, the channel estimation process is carried out by using the pilot symbol PS as a reference for channel estimation and compensating for distortion characteristic in individual CDM channel regions corresponding to positions of the pilot symbols PS of the pilot channel signal.
However, there is a problem in that it is difficult to compensate for distortion characteristic in CDM channel regions corresponding to segments having no pilot symbols, such as CDM channel control data D3˜D22 and D27˜D46, and the channel estimation process needs to be carried out using more channel estimation sequences in multipath channels for accurate channel estimation.